Daryl Hannah has made headlines for opening up publicly about being autistic, a diagnosis she received as a child. Hannah is 52 and a woman, which makes her what some people consider to be a rare entity in the autistic population: female and middle-aged.

Hannah could not, as a child, have received a diagnosis of Asperger Syndrome, as that diagnostic category didn't exist then--and is about to cease existence again. Her autism, she has said, left her with debilitating shyness and a need to rock for self-soothing and made public events a terror for her. At the time she was diagnosed, Hannah has said in interviews, medical professionals recommended that she be medicated and institutionalized. Instead, she went on to act in some movies you might have heard of before transitioning to a quieter life.

When it comes to autism and being a girl or woman, a unique set of issues emerges. Autism is frequently described as a condition that affects three or four times as many boys as girls. In addition, girls who are diagnosed at a young age tend to exhibit more intense symptoms of autism. What that implies, at least for some experts, is that girls and women often go undetected, not standing out as much from their peers as autistic boys across the spectrum might.

In other words, Hannah's experience of being an autistic female might be more common than many people think. Writing at SFARI.org, autism researcher Meng-Chuan Lai discusses some reasons that the detection radar tends to miss autistic girls and women. He notes that autism, as defined and diagnosed today, skews to identifying males because they have been the predominate clinical research population for autism since Kanner and Asperger first characterized the condition. Indeed, the absence of girls and women from autism research has led one investigator to call them "research orphans."

Autistic girls and women, Lai writes, share the "same core cognitive-behavioral characteristics" as autistic boys and men. But because girls and women tend to have a different suite of behaviors from males, autism or not, their version of autism tends to differ from that of boys and men.

An example is the assumption that autistic people lack creative or imaginative thinking. Autistic girls can and do engage in imaginative play. Autistic girls and women also overall tend to lack one of the keystones of an autism diagnosis, repetitive and stereotyped behaviors, illustrating how the criteria skew to identifying boys.

Lai also points out the clinical focus on boys in autism-related studies and the fact that girls are overall diagnosed later in life. In addition, unless a autistic girl has accompanying intellectual disability or other issues, she is less likely than a boy with the same traits to receive an autism diagnosis. And because autism is considered a "male" condition, autistic girls and women can find themselves instead misdiagnosed with a variety of disorders. Obviously, this misdiagnosis carries repercussions that can include misapplied interventions, wrong assumptions, and lack of much-needed understanding and support.

These clinical distinctions between the sexes aren't simply a matter of subjective interpretation, according to some of Lai's own research. Noting that the results are only a beginning, he writes about differences he's identified in brain volume measurements between autistic girls and autistic boys. His team has found that

... the brains of females with autism have a shift toward looking like typically developing males rather than typically developing females. Interestingly, males with autism also show a shift, but in another direction (though with less strong evidence): They shift toward typically developing females rather than typically developing males.

One key difference between girls/women and boys/men with autism lies in the generally different social lives and social expectations of girls and boys. Autistic girls seem to be better at copying what they see others doing socially. When they are younger, their autism-related behaviors tend to help them because they can come across as less disruptive, being absorbed in their own interests. They fly under the radar until they reach an age where they're expected to be socially able with other girls, and then the differences can become stark.

Overall, studies indicate that girls might be better at compensation for the social deficits that accompany autism and hiding them from others in exactly the way Daryl Hannah says she has done. But, as with Hannah and her outward success, that doesn't mean they aren't always working exhaustingly hard to do it. Indeed, Hannah became so weary of the struggle that she walked away from Hollywood to find some peace with her boyfriend and a rescue pig named Molly.